The design and implementation of an asymmetrical Doherty power amplifier are\ndiscussed, where two Cree GaN High Electron Mobility Transistors (HEMTs) devices are used for\ndesigning an asymmetrical Doherty power amplifier to achieve saturated power of 48 dBm and\noptimal back-off efficiency of 8 dB in the frequency band of 3.3-3.5 GHz. Rogers RO4350B material\nis used as a substrate material, a back-off of 8 dB was achieved with an average gain of 10 dB. Loadpull\ndata are an important tool for determining the optimum load impedance that the transistor\nneeds to see. Additionally, the measured efficiency was 50% when the designed amplifier was tested\nby a modulated signal of 8 dB peak-to-average-power ratio when the average output power was 40\ndBm. At the same time, the linearity of the designed amplifier was measured and found 31.8 dB\nwhich can be improved using a digital pre-distorter. The gain phase measurement can be used as\nan indicator for compensating the phase difference between the two cells.
Loading....